New Study Finds COVID-19 Virus Commonly Infects White-Tailed Deer in the United States
The coronavirus responsible for the ongoing COVID-19 pandemic is not only infecting humans but has also been found to commonly infect white-tailed deer, according to a new study. The research suggests that the virus is evolving rapidly in these animals, raising concerns about its potential spread to humans and other wildlife.
Previous studies have shown that SARS-CoV-2, the virus that causes COVID-19, may be prevalent among white-tailed deer in certain parts of the United States. In this latest study, researchers swabbed the noses of free-ranging deer across Ohio to test for SARS-CoV-2 infections. Between November 2021 and March 2022, they sampled 1,522 deer in 83 out of the state’s 88 counties.
The genetic analysis of these swabs revealed active SARS-CoV-2 infections in 10 percent of the deer, with at least one positive case found in 59 percent of the tested counties. Blood samples collected from the deer also indicated that almost 24 percent of them had been infected with the virus at some point.
What is concerning is that genomic analysis suggests that at least 30 of the active infections found in deer were transmitted from humans. This indicates a bidirectional transmission between humans and animals, with the virus easily jumping from one species to another.
Andrew Bowman, a veterinary epidemiologist at Ohio State University and co-author of the study, stated, “We generally talk about interspecies transmission as a rare event, but this wasn’t a huge sampling, and we’re able to document 30 spillovers. It seems to be moving between people and animals quite easily.”
White-tailed deer could potentially serve as a reservoir for the virus, spreading it to other wildlife, livestock, and humans. The researchers found that the coronavirus was most prevalent among deer living near densely populated areas.
The study also detected the presence of highly contagious variants such as the delta variant and the alpha variant among the deer. The genetic makeup of these variants matched those circulating among humans at the time, suggesting spillover events from humans to deer.
Furthermore, the study found that the virus evolves more rapidly in deer than in humans, as observed through mutations in the viral samples. While the implications of this rapid evolution are still unclear, it raises the possibility that the virus could continue to evolve in deer and potentially spread back to humans.
However, the study also provided some reassurance regarding the effectiveness of COVID-19 vaccinations. Syrian golden hamsters, commonly used in SARS-CoV-2 research, were exposed to coronavirus variants taken from white-tailed deer. Vaccinated hamsters displayed milder symptoms compared to unvaccinated hamsters, suggesting that the vaccines could offer some protection against variants from deer.
Even with this positive finding, there are still concerns about the impact of the virus on domesticated animals and wildlife. The study highlights that approximately 70 percent of free-ranging white-tailed deer in Ohio have not been exposed to SARS-CoV-2. This raises questions about the potential pathways for the virus to spread among other animal hosts.
“This trajectory continues for years, and we have a virus that becomes deer-adapted, then does that become the pathway into other animal hosts, wildlife or domestic? We just don’t know,” says Bowman.
The study, published in Nature Communications, underscores the need for continued monitoring and research to better understand the transmission dynamics and potential risks associated with SARS-CoV-2 infections in wildlife populations.